When multiple URLs were passed and some succeeded but others failed,
the fallback re-opened all URLs via /usr/bin/open, causing duplicates.
Now only failed URLs are passed to the system open fallback.
Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>
(cherry picked from commit 3790b0c0f0b98286b78f6f5aa8dbc9756cf756e8)
When running `open https://...` inside a cmux terminal, the URL now
opens in the built-in browser panel instead of the system default
browser. Non-URL arguments and explicit flags pass through to
/usr/bin/open unchanged.
Closes#306
Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>
(cherry picked from commit 174623776eb0baef04f5a9ab49b926427c149acd)
